Why I stopped using the Tom Bihn Synapse 25

The Tom Bihn Synapse 25 gets some of the highest ratings around in the traveling community. Go onto most any forum to do with EDC, traveling, airports and luggage, or even preparedness, and you’ll get recommendations to look at Tom Bihn.

And without a doubt, the Synapse 25 excels at some things above and beyond what I’ve seen in any other pack – namely its organization and pocket layout. The light weight is fantastic, too. Over the past year, I’ve been using a Synapse 25 every single day for EDC, travel to several different countries, and work. I’ve probably logged hundreds of “back hours” (if that’s a thing) with this. In one case I even used it as my only bag on a one week work and travel flight to Wales.

But I also have significant problems with the Synapse 25, which caused me to ultimately stop using this pack. And because I’ve seen none of these mentioned in the glowing reviews of this pack elsewhere, I figured someone needs to talk about it.

The Synapse 25’s backpanel causes overheating, sweat, smell

The back panel and shoulder straps are rather basic and provide no ventilation whatsoever. So when I used this pack on a three month trip to Thailand, or during the summer in Europe, my back and shoulders got seriously hot. And sweaty. Very sweaty. And all the mesh backing and shoulder straps do is absorb that sweat, and then begin to smell.

And unfortunately, that smell is hard to wash out. Regular detergent didn’t work for me – the forums recommend you obtain some kind of special chemicals and soak it in a tub, a hassle or downright infeasible when traveling. And when I did finally wash the smell out, it was back within 3-4 days of active use. What’s the point of wearing merino baselayers that don’t smell if your synthetic pack reeks from several feet away? I feel as though a lot of the praise put upon this pack comes from people who don’t actually use it much, or who don’t have a summer where they live.

While most modern hiking packs have mesh foams designed for breathability by creating gaps for airflow where your back is, or by suspending the pack itself an inch or two from your back, the Synapse 25 takes advantage of none of these developments. This makes this pack seriously uncomfortable and smelly to use in hot climates. Even my 9 liter hydration pack from Black Diamond has holes in the back padding to aid in ventilation.

No suspension system – carrying a heavy load is uncomfortable

Modern hiking packs also have a suspension system with a frame sheet or stays and a hip belt. While not necessary for very light loads, when I want to load up more than about 14lbs into my pack, I like to transfer that weight away from my shoulders and spine, and onto my hips, where 60-80% of it is supposed to sit. Now, normally I would understand why they chose to avoid the added weight and cost of this on a 25 liter pack (although the Synapse 25 costs more than hiking packs twice its size coming from good brands like Osprey, Gregory, and Black Diamond), but Tom Bihn’s Guide Pack, at 31 liters and specifically designed for hikes into the mountains, has no hip belt either.

Gossamer Gear make a 60+ liter pack (called the Mariposa) with a full suspension system and hip belt, and they make it weigh almost a pound less than the Guide’s pack. Hip belts don’t need to weigh a ton.

Durability issues with the zippers’ waterproofing

The Synapse 25, together with most of Tom Bihn’s range of bags, use some really nifty waterproof zippers. The problem is, they’re not durable. After about 6 months of use, the material that’s supposed to close together and keep the water out on my zippers started fraying. I sent an email to customer support and they said this was normal. Well, the zippers kept fraying, and there are now gaps (see picture below) that let water through. Also somewhat importantly, the bag’s looks took a turn for the worse. If you have to use a pack for somewhat important occasions, it’s preferable for it not to look like it’s falling apart.

I’ve had a waterproof jacket from Arc’teryx for twice as long as this backpack and it’s seen at least as much use, yet the waterproof zippers there are perfectly fine. If you search the Tom Bihn forums, you’ll see that the zipper issue is quite common and people run into it after a few months to a few years of use, probably depending on whether you use the pack every day or not. Since this is a known problem, I would suggest Tom Bihn change to more durable waterproofing on their zippers. To clarify, the actual integrity and motion of the zippers themselves has remained perfectly fine, it’s the waterproofing on top that’s been failing.

Despite all of this, the Synapse 25 would still make a great pack for many people. Anyone living in cooler places where back ventilation is irrelevant would be fine, and if you’re going to keep the load inside your pack to a minimum, you won’t need any frame sheet or stays with a hip belt. But for the price of the pack, which is almost $200, you can get yourself an excellent hiking pack that takes advantage of the last few decades of advancements in pack fitting and carry, and still have $100 to spend on other gear. Or pie. Lots and lots of pie 🙂

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14 thoughts on “Why I stopped using the Tom Bihn Synapse 25”

Good critique of this pack and to be honest, just based on what I’ve seen and heard of the pack… I can totally see all of this being a real issue and honestly the main reason I haven’t ordered one yet. The only problem I see with this article is the lack of a more fully fleshed out recommendation, you seem to have considerable experience with the kind of backpacking use that a lot of people who consider the Synapse would want and a few recommendations would be great. That Gossamer Gear pack looks nice, but it also looks far too large for what I would call comparable to the Synapse.

Thanks, and you have a good point. The reason I’m not suggesting any solid recommendations is because I’m still very much on the lookout! Right now I’ve settled on the Goruck GR1, but that pack also has some limitations, and is even more expensive than the Synapse – but at least there are no issues with durability and the back and straps don’t start to smell. But there’s still no hip belt and the pack is heavy on its own, meaning that it won’t really be comfortable unless you have a *very* lightweight load – something that I’m striving for anyway.

Another interesting pack I’ve seen but not held in my hands is the Vertx EDC Gamut – although it’s the complete and total opposite of the Goruck GR1. It has a ton of organization and features which I personally just don’t need. When you travel with as little stuff as me, it’s just not necessary.

My experience with hiking packs with hip belts has been mediocre. Even the ones with adjustable torso lengths don’t seem to fit me well. I’ve had or have 2 Gregory, 1 Osprey, 1 Mystery Ranch, 2 Deuter, 1 Granite Gear, 1 Gossamer Gear, and 1 Black Diamond pack and I’m not really that happy with any of them for traveling. For going on 3-5 day backpacking trips with camping gear the Gossamer Gear pack is fantastic. Really light and very comfortable, but that’s a different category of use.

For now, after a month of use, the GR1 is doing everything I need it to. It has almost no excess straps or webbing anywhere, is very durable, has a minimal profile and no unnecessary organization, but it’s also heavy and all that weight sits on your shoulders.

Anyway, if anyone else has further suggestions for packs, please put them down in the comments section!

I’m currently using the Mavic Crossmax hydropack for such purposes (small hiking/etc), which you may find somewhat interesting, here’s why:

Pros:
– it’s waterproof without a bag cover
– it has a camelback pocket + water tube routing and mouth piece retainer
– it has quite a few pockets, including waist belt pockets
– it has 2 internal compartments which fully open (fully zippered so the bag opens like a GR1). One of em can fit a 13″ laptop if you get the bigger bag (the small bag is really small and can only fit a tablet)
– it has a good ventilation (large separate pads on the back) as it’s made for MTB (sweat a lot on MTBs)
– its light
– good zippers with awesome zipper handles
– it has an extension on the bottom should you need another 15L+ (its used for bike helmets but works for anything really, a big jacket, a tarp, whatever)

Cons:
It’s not as classy looking as some other bags (it’s an MTB bag.. so looks like “sport equipment”)

So all in all while it’s not conventional I love this bag and have found nothing that comes even close in term of functionality, that isn’t another MTB bag.

Thanks for sharing your review!
I was just about to pick up the Synapse 25 but now I’m going keep looking. I have been eyeing the Goruck GR1 but the price tag seems steep for what you get. Now that you have had one for a while are you still happy with it?
I looked up the Vertex Gamut based on your comment and I even viewed one today. Very nice pack but the interior is lined with a velcro friendly fabric to accommodate accessories. That has kind turned me off from the Gamut. I’m currently looking at the Tasmanian Tiger TT Combat pack. It has a hip belt thats removable, some storage but nothing excessive.

Thanks for the feedback. I also use the Synapse 25 for everyday carry, but not to the extreme you use it. I love the geometry of the back and how I am able to organize my daily carry items. I use it primarily for work, so I don’t usually break a sweat from the car to the office. I will keep a look out for the zipper issue you mentioned. So far the pack has performed perfectly. Good luck in the hunt for the right pack for you.

I think you should try the Synapse in black because it uses the same material as GR1. If GR1 doesn’t smell, then the one in black shouldn’t as well. One problem down.

The Synapse do have a waist belt, but I think it’s sufficient enough to distribute weight. Although, I have the Synapse 19, which makes me carry less things in general.

And I think the zippers are different now from the one that you have. I notice that the teeth are showing in mine (I just bought mine a month ago) instead of having the guard cover the zipper teeth.

I’m trying to look for the “perfect” backpack to travel with right now. I looked into GR0/echo (small because I am a small person), but they don’t have as much pockets as I would like unfortunately. 🙁 I think Synapse is probably the closest backpack that I find “perfect”… Let me know what you think or if you have any suggestions!

The part of the Synapse that smelled was the mesh material in contact with the back and to some extent also the shoulder straps, which I think are made of the same material regardless of which Synapse version you buy. The GR1 however is made with cordura everywhere.

The Synapse does indeed have a waist belt, but I was referring to a padded hip belt. Waist belts are not there to distribute weight, they’re there to stabilize the pack during movement (e.g. if running or climbing). If you were to try and distribute weight using a thin strap like the one for the Synapse you’d end up with blisters on your waist. Trust me, I’ve tried.

I hope they really did improve the zippers, because there are some other Tom Bihn items that I’ve been looking at but had to dismiss for that reason.

Yes, the Goruck packs lack pockets in general, it’s mostly a cavernous inner area with a few pockets here and there. The Synapse has far superior pocket layout and organization, that’s for sure. I’m afraid I still don’t have any other suggestions. So far though I’ve been very happy with the Goruck, since whatever it lacks in internal organization I make up for with various organizer pouches that are all neatly stacked in there.

thats interesting indeed. i wonder if the cordura (ie nylon) is comfy enough. wet/smelly/bad vent in backpacks padding seem to always be an afterthought yet very important to me.

Also, the waist belt vs no waist belt is always a hard one for packs of this size.

when hiking they’re more than desirable. when city-hopping they’re an annoyance. and retractable ones aren’t all that nice.

thanks for the review by the way, this was quite informative. it would be good to figure out if tombihn fixed the waterproof zippers issue, since this one is unacceptable at their price point IMO (while other things are more like “design decisions”)

Amen. Same exact problems. Love the design, fails on purposeful execution. Wish I could love the packs but the sweat, smell, and the other faults listed rule it out. Anyone want to buy a Synapse 19 in black? Washed of course.

Midori- the material is the same but not the way it’s constructed just see how much heavier the gorucks are.

If you plan on “backpacking” with this pack and 25L then you bought the wrong pack. This is an edc bag for school, work, etc. And if you made it smell that bad maybe you should look into showering more. I use a GR2 for rucking and workouts and it never smells. Go buy an Osprey if you’re going to backpack all over the world.

You can absolutely travel with a Synapse, and 25L is enough to travel for months if you’re packing light. I’ve even managed with a 10L bag (single shoulder backpack, holds around a third of an S19) so I could use the S19 quite happily.

I’ve had the Synapse 25 for over 2 years now, it’s my *exclusive* travel and day-to-day bag, and have had none of these issues. Perhaps the zipper issue is merely an older model, and I never have rain issues. As for the smell, I travel in hot climates where my only bag is my Synapse 25, while I do get a sweaty back, I never have had any issues with smell, in fact this is the first I even considered it. There has to be something with your bag specifically, because that just seems really weird. I do understand what you mean about this hip strap, but find the one that comes with it is totally find for travelling purposes if I’m carrying a particularly heavy load. It’s definitely not a hicking backpack – though I’d imagine you could get padded straps for it pretty easy.

You should check out the current synapse by Tom Bihn. The zippers are reversed so the waterproofing is on the inside. So there should be less of an issue of those flaps breaking down. They also offer a internal frame to purchase to retrofit the synapse with a frame. That frame helps with load issues and you can also have the bag sit slightly off your back and on your hips using the frame sheet, possibly helping with any ventilation problems. Also offered as an add on accessory is a padded hip belt but I’m unsure how effective that is.
My main issue are the shoulder straps. They are super rough and thin. But I guess I’ll have to get used to them.